Let's break this down. We're going to add 1335 and 8171 together.

Step 1: We'll start by adding the digits 5 & 1 in column 1 and get 6.

Step 2: We'll start by adding the digits 3 & 7 in column 2 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 3 & 1 in column 3 and get 5.

Step 4: We'll start by adding the digits 1 & 8 in column 4 and get 9.

So, 1335 + 8171 = 9506.

